Method and apparatus for conditioning air



May 16, 1933. H. o. FORREST ET AL 1,909,823

I METHOD AND APPARATUS FOR CONDITIONING AIR Filed Nov. 21, 1931 2 Sheets-Sheet l ATTORNEYS METHOD AND APPARATUS FOR CONDITIONING AIR Filed Nov. 21, 1951 2 Sheets-Sheet 2 INVENTORS Mrgd Fbrrasl- BY Z-e Van Horn 4 M WW ATToRisEvs Patented May 16, 1933 srrss PATENT OFFICE HENRY O. FORREST, OF TEANEGK, AND LEE VAN HORN, ELIZABETH, NEW JERSEY METHOD AND APPARATUS FOR coiimrromue Am Application filed November 21, 1981.

This invention relates to air conditioning and more particularly to a process and apparatus for conditioning air for rooms, residences and closed vehicles, such as railroad trains, and contemplates, as a part thereof,

imparting to air characteristics of temperature and humidity for bringing the air being conditioned within the healthful comfort range and the provision of mechanical'units for ,efi'ecting that result.

According to our invention, we provide an air conditioning system Wherein air is first dehumidified by contacting it with a spray of a hygroscopic fluid of controlled concentration and which gives the air desired characteristics of humidity. This hygroscopic fluid may be lithium, calcium or zinc chloride brine or any other suitable liquid which has an aflinity for water. The dehumidifying step may be carried on isothermally with respect to the air by cooling the dehydrating liquid so that the air, when it leaves the dehumidifier, may have the same dry bulb temperature that it had when it was admitted to the chamber.

The air is next conducted to a cooling chamber where it contacts a cooling coil and is cooled to the desired temperature. A chamber is also provided to cool the fluid circulated through the cooling coils by bringing it in association with another fluid having lower vapor characteristics. By virtue of the difference in the vapor pressure of this second fluid and the first fluid,

5 some of the first fluid is evaporated and by the step of evaporation the remaining part of the first fluid is cooled. As an example, when a saturated solution of calcium chloride is used as a cooling agent, and at an 9 initial temperature of 83 F., it is possible to cool the water to 43 F. for the vapor pressure of water over calcium chloride at 83 F. is 6.7 mm. which the is vapor .pressure of Water at 43 F. The circulated 5 cooling fluid may also'be cooled by running it through coils immersed in a fluid which is exposed to the action of another fluid of lower vapor pressure characteristics.

A suitable fluid reactivating system is provided to controlthe concentration f the hy- Serial No. 576,488.

- ter cooling device utilizing as a cooling agent a liquid which has water vapor pressure characteristics much lower than water.

These and other objects will be apparent to those skilled in this particular art from the claims and description in the specification in connection with the. drawings in which: F igure 1 is a schematic layout of a device illustrative of the invention.

Figure 2 is a schematic layout of another device illustrative of the invention.

In the embodiment of' the invention,

which has been chosen for purposes of illustration, and now referring to Figure 1 of the drawings; there is shown a dehumidifying chamber 10, having a spray member 11,

dispoged in the upper portion thereof, and a storage tank or sump 12 located in its lower portion. An air inlet duct 14 is adapted to supply air thereto and during operation of the device, a fan or blower 15 provides a suction which draws the air through the chamber 10 in which it is sprayed, by means of the member 11, with a hygroscopic liquid such as lithium, calcium or zinc chloride brine. After passing through the chamber 10, this air is forced by the fan 15 to a cooling chamber 16. In the chamber 16, the air contacts a plurality of coils through which a cooling medium is being circulated and is given desired characteristics of temperature. This conditioned air is then conducted, by means of duct 17, to an air space (not shown) which is being conditioned. A duct 19 connected with the aforesaid air space joins the duct 18 at 20 so that the air delivered to the cooling chamber 16 is really a mixture of p dehydrated-fresh air and air that has already been conditioned and used with, possibly, a small amount of leakage unconditioned air.

The dehydrating liquid sprayed through the chamber 10 flows to the storage tank 12 and is removed therefrom by means of a pipe 21. This pipe 21 has a branch 22 which leads to an evaporator 23 and a branch 24 which leads to a jet condenser 25 and is then pumped through pipe 26 by means of pump 27 through pipe 28 to a cooling tower 30. From the cooling tower 30, the liquid flows through coils 31 to a pipe 32 which conducts it back to the spray member 11. A valve 34 is located in the pipe 22 and controls the amount of fluid delivered to the evaporator 23 for reactivation and a valve 34' is provided in pipe 24 to control the amount of fluid delivered through the jet condenser and suitable pipes to the cooling tower. The pipe 33 is connected to the evaporator 23 at one endand joins pipe 26 at 35, so that the reactivated portion of the liquid, which has been highly concentrated, is mixed with the liquid that has passed through the jet condenser 48. By concentrating the reactivated liquid to a sufficiently high degree, a desired concentration of the entire hygroscopic mixture is obtained.

Heat is supplied to the evaporator 23 by means of a steam coil 36 and this heat evaporates the absorbed water which is discharged from the evaporator through the vent 37 in the form of steam. The reactivated liquid which has been highly concentrated is then mixed with the other liquid in the pipe 26 and is pumped to the cooling tower 30.

The cooling tower 30 may consist of :1. cylindrical casing having an air inlet 42 in the lower portion thereof and an air outlet in its upper portion. A spray member 40 supplies a spray of water to the chamber and a fan 41 forces air through the sprayed water thereby cooling it. This air and any water which it may have absorbed is discharged from the cooling tower to the air outlet 43. The water that has been sprayed across the coils 31 falls to the bottom of the chamber to a sump 12 and is pumped through a pipe 44, pump 45 and pipe 46 to the spray member 40. A new supply of water may be added to this system whenever needed through a water inlet pipe 13 connected to the sump 12'.

The jet condenser 25 consists of a chamber portion 48 connected by a pipe or duct 49 to a water cooling chamber 50. A jet ejector 51 may be connected to the chamber portion 48 of the condenser through a pipe 52 for the purpose of removing non-condensable gases. By virtue of the difi'erence in vapor pressure between the hygroscopic fluid assed through the jet condenser and water which may be sprayed into the chamber 50, through a spray member 60, evaporation of the water in chamber 50 is eiiected. While spraying the water .to be cooled is an effective way of exposing it to the :"absorbing action of the hygroscopic liquid in the condenser 25, a spraying operation is unnecessary to successful operation of the device and the water may be piped into the chamber 50 if desired.

The water. that has been cooled in the chamber 50 passes out of the bottom thereof through a pipe 54, and by means of a pump 55 is. forced through a pipe 56 to coils 57 in the air cooling chamber 16. The cold water within the coils absorbs heat from the dehumidified air which contacts their convection surfaces and this used water, containing absorbed heat from the air, is conducted through a pipe 58 to the spray member 60, located within thechamber 50 and as previously described, is sprayed into the chamber 50 and cooled by evaporation. Obviously, by virtue of the removal of water by evaporation from the cooling circulatory system, it is necessary from time to time to supply additional water to the system. This may be done through a water pipe 61 joining the pipe 58 at 62.

It is obvious from the description of the several mechanical units just given and their cooperation, that an air conditioning system is provided that is capable of imparting to air characteristics of temperature and humidity within a wide range of limits, and by virtue of the cooling chamber 50, in association with the jet condenser 25, with the proper choice of a hygroscopic liquid and regulation of vacuum, a device is provided that will cool water even to the point of freezing.

In the embodiment of the invention illustrated in Figure 2, the dehumidifying chamber, several air ducts, hygroscopic li uid reactivation apparatus and cooling c amber are similar to like apparatus shown in Fig ure 1, and to avoid unduly lengthening the description, have been given the same reference characters and will not be further described.

In this embodiment of the invention, however, in the air cooling chamber 16 instead of contacting the dehydrated air with coils containing a cooling medium, a spray member 100 is provided which sprays the dehydrated air with a cooling fluid of neutral hygroscopic characteristics. This sprayed fluid falls to the bottom of the chamber 16 and is collected in a sump 101. A pipe 102 carries the liquid from the sump 101 to a cooling chamber 50 through which it is conducted in a series of closed coils 103. The

coils 103 are covered by water, the tempera.-

ture of which is reatly reduced by means of a hygroscopic Enid flowing through a jet condenser which may be similar in all respects to thejet condenser and its auxiliary devices which consists of an ejector 51 and suitable connections, 49 and 52, to the cooling chamber 50 as described in connection with the fluid cooling apparatus described in connection With the description of Figure 1.

The cooling liquid of substantially neutral hygroscopic characteristics is cooled in passing through the coils 103 and passes out a pipe 104 and is pumped by means of a pump 105 through a pipe 106 to the spray member 100. A pipe 132 is connected at 133 with the pipe 32 joining the outlet end of the dehydrating liquid cooling chamber and the dehumidifying chamber 10. This pipe 132 has a valve 135 therein which is controlled by a submerged float member 136 through a lever arm 137 and, upon a change in the specific gravity of the cooling liquid of neutral hygroscopic characteristics, is adapted to open o close, as the necessity arises, to increase or decrease the quantity of concentrated hygroscopic liquid admitted to the cooling medium circulatory system. WVhen the valve 135 .opens, the concentrated hygroscopic liquid is admitted to the system through the pipe 138.

An overflow line 1 10 connects the sump 101 of the cooling chamber with the sump 12' of the dehydrating chamber so that if, at

any time, the liquidin the cooling system gets too high, it can flow to the dehydrating system where reactivation with an accompanying discharge of absorbed water vapor is continuously being efl'ected.

By virtue of the air conditioning system.

act to reduce the temperature of the air or in such cases Where air added to the system by means of the air duct 19 has increased the humidity of the mixture to too great an extent, the cooling liquid in the chamber 16 will act to remove most of that excess moisture.

Two specific systems useful in imparting to air desired characteristics of temperature anu humidity have been described at some length and in detail, but it is to be understood that changes, additions, substitutions, and omissions may be made therein within the spirit of the invention as defined by the appended claims.

We claim:

1. The method of conditioning air by the use of a hygroscopic liquid, which comprises introducing air to be conditioned into a dehumidifying zone, introducing hygroscopic liquid into said dehumidifying zone in contact with said air to effect dehumidification thereof, separately withdrawing dehumidified air and diluted hygroscopic liquid from said dehumidifying zone, introducing water into an evaporating zone, contacting water vapor from said evaporating zone in an absorbing zone with hygroscopic liquid, withdrawing diluted hygroscopic liquid from said absorbing zone, withdrawing refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air, concentrating said diluted hygroscopic liquid, and recycling said concentrated hygroscopic through said dehumidifying and absorbing zones. I

2. The method of conditioning air by the use of a hygroscopic liquid, which comprises introducing air to be conditioned into a dehumidifying zone, introducing hygroscopic liquid into said dehumidifying zone in contact with said air to effect dehumidification thereof, separately Withdrawing dehumidified air and diluted hygroscopic liquid from said dehumidifying zone, introducing water into an evaporating zone, contacting water Vapor vfrom said evaporating zone in an absorbing zone with hygroscopic liquid, withdrawing diluted hygroscopic liquid from said absorbing zone, withdrawing refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air, concentrating a portionof'said diluted hygroscopic liquid, mixing said concentrated portion with the balance of said diluted hygroscopic liquid, and recycling said mixture through said dehumidifying and absorbing zones.

3. The method of conditioning air by the useof a hygroscopic liquid of controlled temperature and concentration, which comprises introducing air to be conditioned into a dehumidifying zone, introducing hygroliquidscopic liquid into said dehumidifying zone in contact with said air to effect dehumidification thereof, separately withdrawing dehumidified air and diluted hygroscopic liquid from said dehumidifying' zone, introdrawn dehumidified air, concentrating a.

portion of said diluted hygroscopic liquid by evaporation, mixing said concentrated hygroscopic liquid with the balance of said diluted hygroscopic liquid, cooling said mixzone, introducing water into an evaporatlng zone maintained under reduced pressure,

" contacting water vapor from said evaporating zone in an absorbing zone with dilu"v ed hygroscopic liquid from said dehumidifying zone, withdrawing diluted hygroscopic liquid from said absorbing zone, withdrawing refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air, concentrating a portion of said diluted hygroscopic liquid by evaporation, mixing said concentrated hygroscopic liquid with the balance of said diluted hygroscopic liquid, cooling said mixture, and recycling said mixture through said dehumidifying and absorbing zones.

5. The method of conditioning air by the use of a hygroscopic liquid of controlled temperature and concentration, which comprises introducing air to be conditioned into a dehumidifying zone, introducing hygroscopic liquid into said dehumidifying zone in contact with said air to effect dehumidification thereof, separately withdrawing dehumidified air and diluted hygroscopic liquid from said dehumidifying zone, in-

r ducing water into an evaporaiing zone maintained under reduced pressure, contacting water vapor from said evaporating zone in an absorbing zone with a portion of said diluted hygroscopic liquid from said dehumidifying zone, withdrawing refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air, concentrating the remaining portion of said diluted hygroscopic liquid from said dehumidifying zone by evaporation, withdrawing diluted hygroscopic liquid from said absorbing zone, mixing said concentrated hygroscopic liquid with the diluted hygroscopic liquid withdrawn from said absorbing zone, cooling said mixture, and recycling said mixture through said dehumidifying and absorbing zones.

. 6. The method of conditioning air by the use of a hygroscopic liquid of controlled temperature and concentration, which comprises introducing air to be conditioned into a dehumidifying zone, introducing hygroscopic liquid into said dehumidif'ying zone in contact with said air to effect dehumidification thereof, said liquid being cooled prior to use to such an extent that aoaeas substantially no rise in temperature of the air takes place during said dehumidification,

separately withdrawing dehumidified air and diluted hygroscopic liquid from said dehumidifying zone, introducing water into an evaporating zone maintained under reduced pressure, contacting water vapor from said evaporating zone in an absorbing zone with hygroscopic liquid, withdrawing diluted hygroscopic liquid from said absorbing zone, withdrawing refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air by indirect heat exchange, concentrating a portion of said diluted hygroscopic liquid by evaporation, mixing said concentrated hygroscopic liquid with the balance of said diluted hygroscopic liquid, and recycling said mixture through said dehumidifying and absorbing zones.

7. The method of conditioning air by the use of a hygroscopic liquid of controlled temperature and concentration, which comprises introducing air to be conditioned into a dehumidifying zone, cooling hygroscopic liquid to substantially the wet bulb temperature of the atmospheric air, introducing said cooled hygroscopic liquid into said dehumidif'ying zone in contact with said air to effect dehumidification thereof, separately withdrawing dehumidified air and diluted hygroscopic liquid from said dehumidifying zone, introducing water into an evaporating zone maintained under reduced pressure, contacting'water vapor from said evaporating zone in an absorbing zone with hygroscopic liquid, withdrawing diluted hygroscopic liquid from said absorbing zone, withdrawing refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air by indirect heat exchange, concentrating a portion of said diluted hygroscopic liquid by evaporation, mixingsaid concentrated hygroscopic liquid with the balance of said diluted hygroscopic liquid, and recycling said mixture through said dehumidifying and absorbing zones.

8. The method of conditioning air by the use of a hygroscopic liquid of controlled temperature and concentration, which comprises introducing air to be conditioned into a dehumidifying zone, cooling hygroscopic liquid to substantially the wet bulb temperature of the atmospheric air by indirect heat exchange in a cooling zone, circulating a body of water continuously through said cooling zone, passing atmospheric air through said cooling zone to evaporate and cool said circulated water, introducing said cooled hygroscopic liquid into said dehumidifying zone in contact with said air to effect dehumidification thereof, separately withdrawing dehnmidified air and diluted hygroscopic liquid from said dehumidiitying zone, introducing water into an evaporating zone maintained under reduced pressure, contacting water vapor from said evaporating zone in an absorbing zone with diluted hygroscopic liquid from said dehumidifying' 5 zone, withdrawing diluted hygroscopic liquid from said absorbing zone, withdrawing. refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air by indirect heat ex- 7 10 change, returning said withdrawn water to said evaporating zone, concentrating a portion of said diluted hygroscopic liquid by evaporation, mixing said concentrated hygroscopic liquid with the balance of said 1 diluted hygroscopic liquid, and recycling said mixture through said dehumidifying and absorbing zones. 7

9. The method of conditioning air by the use of a hygroscopic liquid of controlled temperature and concentration, which comprises introducing air to be conditioned into a dehumidifying zone, cooling hygroscopic liquid to substantially the wet bulb temperature of the atmospheric air by indirect heat exchange in a cooling zone, circulating a body of water continuously through said cooling zone, passing atmospheric air through said cooling zone to evaporate and cool said circulated water, introducing said cooled hygroscopic liquid into said dehumidifying zone in contact with said air to eifect dehumidification thereof, separately withdrawing dehum-idified air and diluted hygroscopic liquid from said dehumidifying zone, introducing water into an evaporating I 'zone maintained under reduced pressure, contacting water vapor from said evaporating zone in an absorbing zone with a portion of said diluted hygroscopic liquid from said 40 dehumidifying zone, withdrawing refrigerated water from said evaporating zone and utilizing it to cool said withdrawn dehumidified air by indirect heat exchange, returning said withdrawn water to said evaporating zone, concentrating the remaining portion of said diluted hygroscopic liquid from said dehumidifying zone by evaporation, withdrawing diluted hygroscopic liquid from said absorbing zone, mixing said concentrated hygroscopic liquid with the diluted hygroscopic liquid withdrawn from said absorbing zone, and recycling said mixture through said dehumidifying and absorbing zones. In testimony whereof, we have signed our names to this specification this 17 day of November, 1931.

.. HENRY O. FORREST.

LEE VAN HORN. 

